Revelation 14:1-3

¹And I saw, and behold, the Lamb standing on the mount Zion, and with him a hundred and forty and four thousand, having his name, and the name of his Father, written on their foreheads. ²And I heard a voice from heaven, as the voice of many waters, and as the voice of a great thunder: and the voice which I heard [was] as [the voice] of harpers harping with their harps: ³and they sing as it were a new song before the throne, and before the four living creatures and the elders: and no man could learn the song save the hundred and forty and four thousand, [even] they that had been purchased out of the earth.